B97.33
Human T-cell lymphotrophic virus, type I [HTLV-I] as the cause of diseases classified elsewhere
B97.33 (also written B9733) is a billable ICD-10-CM diagnosis code for human T-cell lymphotrophic virus, type I [HTLV-I] as the cause of diseases classified elsewhere. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 20 codes in category B97 (Viral agents as the cause of diseases classified elsewhere). The Alphabetic Index lists it under 5 entries. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 5 Excludes2 entries.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
When an infection is classified outside Chapter 1 and no organism is part of its code, an additional B95, B96 or B97 code identifies the organism.
Use additional code
Add the listed code as a secondary code, if known.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (5 notes)
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
IRF 60% Rule
On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.
Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026Hospice: not accepted as primary
Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Supplementary or additional code, not allowed as principal diagnosis.
Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 8 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIncludes
Further defines or gives examples of the content of the category.
Also from chapter/block level (1 note)
- diseases generally recognized as communicable or transmissible
Notes
Also from chapter/block level (1 note)
- These categories are provided for use as supplementary or additional codes to identify the infectious agent(s) in diseases classified elsewhere.
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 5 entries
- Human, T-cell lymphotropic virus, type-1 (HTLV-I) infection, as cause of disease classified elsewhere
- Infection, infected, infective (opportunistic), retrovirus, as cause of disease classified elsewhere, human, T-cell lymphotropic, type I (HTLV-I)
- Infection, infected, infective (opportunistic), virus, viral NOS, as cause of disease classified elsewhere, human, T-cell lymphotropic,, type I (HTLV-I)
- Infection, infected, infective (opportunistic), virus, viral NOS, as cause of disease classified elsewhere, retrovirus, human, T-cell lymphotropic,, type I (HTLV-I)
- Retrovirus, as cause of disease classified elsewhere, human, T-cell lymphotropic, type I (HTLV-I)